It's a win-win.. They help themselves and the network as a whole. Incentives working as designed :)

They can boast about how their users enjoy lower fees, and they can reduce their own operating expenses when consolidating their own outputs. Plus and they help increase tx throughput and lower fees on the entire Bitcoin network.

https://medium.com/bitfinex/bitfinex-adopts-segwit-8e6c5d72fcf9

https://cdn-images-1.medium.com/max/800/1*XfImgygIyMSKGklJ40BwYA.png